The invention relates to a plasma melting furnace comprising one or more plasma burners penetrating the furnace lining, in particular a plasma burner projecting vertically into the interior of the furnace.
With known plasma melting furnaces the brickwork is made cylindrical. The thermal energy radiation coming from the plasma jet involves a big stress on the lining. The thermal radiation dissipating onto the cylindrical lining in a plane perpendicular to the axis of the cylindrical brickwork is reflected in this plane by the brickwork, causing a very high temperature stress and thus a strong temperature increase of the lining in a band region of the lining lying in this plane. In practice, this has lead to a premature termination of the furnace campaign, since in particular the zone in the region of the lining closely above the bath level of the furnace is thermally overstressed. The remaining part of the lining would still be useful; the overstressed part of the lining, however, has to be restored prematurely. This band-like damage of the lining, to a particularly great extent, occurs in the lining of small plasma melting furnaces in which the plasma burner projects vertically into the interior of the furnace, because the strongest heat radiation is perpendicular to the axis of the plasma jet.